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Context. First Epoch astrometric and radiometric information of a survey in the optical along the Galactic fourth quadrant is archived for further analysis in the time-domain. Aims. A photographic survey of 1.9 × 10 6 stars down to B-magnitude 14 ± 0.5 along the galactic meridian l = (330 ± 5) ◦ , −64 ◦ ≤ b ≤ −7 ◦ and along the galactic equator 272 ◦ ≤ l ≤ 341 ◦ , |b |≤ 7 ◦ , is provided from century old astrographic plates of Sydney Observatory. Stellar candidates to investigate the Galaxy disk kinematics up to a distance of 1 kpc from the Sun are tentatively selected. Methods. The early data are combined with late epoch observations into a set of 4.8 × 10 5 stars with significant proper motion µ ≥ 0.005 �� yr −1 and approximate color B − V. The selection effects and the kinematical bias on the stellar system are investigated. F-G stellar candidates with a mean transverse velocity dispersion of 45 km s −1 are suggested. Results. The spin rate of 1 ◦ pc −1 of the velocity ellipsoid along its long axis is observed over half a thickness of 25 pc of the galactic disk for stars at an estimated distance D ≤ 300 pc from the Sun. Conclusions. A catalogue of 4.8 × 10 5 stars is provided for further investigation of the galactic disk heating by transient spiral wave 1. Retrospective of early astrographic surveys First epoch observations used in the proper motion (p.m.) determination of faint stars observed in the Tycho-2 catalogue are based on short exposure plates observed for the Astrographic Catalog (AC) at the beginning of the 20th century over a field of

Context. This work is part of a program of proper motion measurements in the Bordeaux Carte du Ciel zone. Aims. We present the CdC2000 catalogue issued from the reduction of the complete Bordeaux Carte du Ciel zone observed at the begining of last century with the Bordeaux astrograph. Methods. Plates have been individually reduced using the TYCHO-2 Catalogue as the astrometric reference. Results. This catalogue is a positional catalogue of 344 781 stars covering the declination zone +11 +18 . The average epoch of positions is 1914.7. The data are from the 512 Carte du Ciel plates archived at the Bordeaux Observatory and scanned with the APM Cambridge automatic measuring machine.Astrometric standard errors are about 0.10 00 to 0.12 00 on positions and 0.6 magnitudes on photographic magnitudes. Conclusions.A detailed study of errors and a comparison of various reduction methods are presented in order to take into account the significant propagated errors from the reference catalogue. The CdC2000 provides positions at the epoch of the plates for 50 682 TYCHO-2 stars. The associated positions are proved to be p 2 more precise than the positions given by the TYCHO-2 catalogue at the epoch of the plates (0.11 00 instead of 0.15 00 ). This work is part of a program of proper motion measurements in the Bordeaux Carte du Ciel zone.

A magnitude-limited photographic survey of relative proper-motion components and B, V photometry of 1.3 × 106 stars brighter than apparent B magnitude 14.5 ± 0.5 in the fourth Galactic quadrant is converted into a distance-limited survey of 3.26 × 105 stars up to a distance of 500 pc. A streaming motion of 13.5 ± 0.5 km s-1 is detected in 4.1 × 104 Population I stellar candidates with an orbital perigalactic center located at 6.8 kpc ≤ R ≤ 7.2 kpc, with a Sun location Rsol = 8.5 kpc. A density perturbation of ~0.1 M⊙ pc-3 in the Galactic field potential at R0 ~ 6.8 kpc is interpreted as resulting from the density wave connected with the Sagittarius-Carina spiral arm. A set of 1.4 × 104 stars of mass ~1.5 ± 0.75 M⊙ identify a pitch angle of 10° ± 1° and a migration time from the Sagittarius spiral arm into the greater solar neighborhood of ~35 Myr.

Variations in the flux and profile of the broad Hα component in the Seyfert galaxy NGC 4151 are analyzed based on spectral observations acquired from 1976 to spring 2003. The procedure used to distinguish components is described. There is a strong correlation between the flux of the broad Hα component and the U flux of the galactic nucleus. There was an appreciable increase in the intensity of the broad Hα in 1990–2000, with the flux reaching a maximum in 1996. The intensity and shape of an emission feature that appeared in the red wing of the broad Hα component at the end of 2002 are estimated.

As a result of the cooperation between the Sofia Sky Archive Data Center (Bulgaria) and Bamberg Observatory (Germany), Royal Observatory of Edinburgh (UK), Konkoly Observatory (Hungary), Strasbourg Observatory, Institute of Astronomy in Cambridge (UK), etc., a programme for investigation of the long-term behaviour of the Pleiades active dwarf stars (in particular, flare stars) is in progress. Existing plates in the Pleiades are found in different European plate archives, made since the end of the nineteenth century, by the searching tool of the wide-field plate database (http://www.skyarchive.org), which provides detailed information for astronomical plate archives all over the world, as well as for plates themselves. We investigate the Pleiades flare stars (UV Cet-type stars) included in the flare Stars database and identified in the USNO A2.0 catalogue. 68 Pleiades plates are already digitized with different scanning machines such as PDS 1010 (Sofia), PDS 2020 (Munster), SUPER COSMOS (Edinburgh), APM (C...

The visual interstellar extinction in the Northern and Southern Coalsack regions is estimated from a photographic survey of proper motion and B, V photometry of 6 × 104 stars as faint as apparent magnitude 14 over a field of view of 6° × 6° in each region. Each cloud is located at a distance of about 160 ± 50 pc from the Sun and exceeds the mean interstellar extinction by more than 0.7 ± 0.1 mag. Galactic plane orbits of 103 stars located at the same distance of 160 ± 50 pc from the Sun in these regions show a semimajor axis of 8.45 ± 0.15 kpc and a mean inclination of 03 ± 02 over the Galactic plane, suggesting a mean impact parameter of 9 ± 3 pc with diffuse clouds of relative velocity on the order of 4 ± 1 km s-1. The weak distant encounter of stars with the cold neutral medium can be explained by a mean mass of about 2500 ± 1250 M⊙ for the gas and dust content in order to account for the diffusion of stellar orbits. A mean displacement of 0012 ± 0001 yr-1 of the western limb of the Southern Coalsack is estimated in the northwest direction and permits a search for strong close stellar encounters. The transfer of angular momentum between the interstellar medium and the scattering of stellar orbits resulting from the encounters suggests a dissipation rate of (2.0 ± 0.7) × 10-4 M⊙ yr-1, leading to an equipartition time of 12 ± 4 Myr. A spin rate of 0.25 ± 0.05 km s-1 pc-1 of the diffuse clouds in the Southern Coalsack is measured and interpreted as the result of the perturbation induced by stellar systems during flyby encounters with a crossing time of 3 Myr, suggesting a cloud core radius of 1 pc.

First orbits have been calculated for the visual binaries WDS 00090-5400, 01061-4643, 05248-5219 and 08447-5443 (Alzner & Argyle 2000; Argyle & Alzner 2000). The current period for the orbit of WDS 18068-4325 (Wierzbinski1958) is too short to represent recent observations. The period has been lengthened to 450 years (Alzner & Argyle 2001). For 00090-5400 the period is 221 years with a moderate eccentricity; 01061-4643 is currently near periastron but is underobserved; 05248-5219 has passed periastron but there have been no observations since 1993. The visual component of WDS 08447-5443 (= δ Vel), which is not the same as the eclipsing component recently discovered by Otero (2000), has an unexpectedly short period.

A set of four test regions covering a total celestial area of 520 deg2 at low galactic latitude is investigated on a set of 130 century-old astrographic plates. About 8% of the 2 × 105 stars with apparent B magnitude 10–14 and with total proper-motion component larger than 002 yr-1 show a significant flickering greater than 0.4 mag in B over a timescale shorter than 20 minutes. About 25% of these stellar flare candidates concern stars with B-V ~ 0.2 (spectral type A7). A procedure to select pre–main-sequence stellar candidates from the distance-limited sample of 16 × 103 disk dwarfs with detected flickering in B magnitude ≥0.4 is presented in view of a mass loss of 10-8 M☉ yr-1, derived from the analysis of the angular momentum distribution of stellar orbits. Follow-up UBV photoelectric photometry at the present epoch of 200 nearby stellar flares along the Vulpecula Rift shows an effect of reddening in B-V and of blueing in U-B for about 10% of the targets. The detection of optically thin or thick disks around the selected targets is suggested. The success rate in detecting optical flares in nearby stars of ~1.5 M☉ with as much as 5 × 10-6 M☉ dumped onto the central star during the past 100 years, from deep astrographic plates coupled with 1 m–class telescope is estimated to 10% with a kinematical bias that can be dealt with.

On a clear, dark night several thousand stars can be seen at any one time. They form familiar patterns such as the Great Bear and Cygnets in the northern hemisphere and Scorpio and Crux in the south. The distances are so great that we see the constellation patterns essentially unchanged from those seen by the Ancient Egyptians for instance. This is partly due to the fact that some of the bright stars in constellations are in what are called moving groups—a loose association of stars moving through space together. More tightly bound are clusters of stars such as the Pleaders or Seven Sisters which appears in the northern sky in the late summer. Eventually the moving groups and clusters of stars will gradually disperse because the distance between the stars is such that the gravitational attraction between the members is relatively weak.

This is the process by which basic material such as gas and dust becomes a gravitating, self-luminous object. This is a complex process involving physics and chemistry, gravitation, rotation, magnetic fields and turbulence, and temperature, density and scale. Binary and multiple stars appear to be preferentially formed during this process so studying these systems in all their variety from the protostellar origins in the sub-millimeter regime to the long period visual systems helps to contribute to the details needed to interpret the process of formation.

One night late in 1918, astronomer William Milburn, observing the region of Cassiopeia from Reverend T.H.E.C. Espin’s observatory in Tow Law (England), discovered a hitherto unrecorded double star (Wright 1993). He reported it to Rev. Espin, who measured the pair using his 24-in. reflector: the fainter star was 6.0 arcsec from the primary, at position angle 162.4\(^{\circ }\) (i.e. the fainter star was south-by-southeast from the primary) (Espin 1919). Some time later, it was recognized that the astrograph of the Vatican Observatory had taken an image of the same star-field a dozen years earlier, in late 1906. At that earlier epoch, the fainter star had been separated from the brighter one by only 4.8 arcsec, at position angle 186.2\(^{\circ }\) (i.e. almost due south). Were these stars a binary pair, or were they just two unrelated stars sailing past each other? Some additional measurements might have begun to answer this question. If the secondary star was following a curved path, that would be a clue of orbital motion; if it followed a straight-line path, that would be a clue that these are just two stars passing in the night. Unfortunately, nobody took the trouble to re-examine this pair for almost a century, until the 2MASS astrometric/photometric survey recorded it in late 1998. After almost another decade, this amateur astronomer took some CCD images of the field in 2007, and added another data point on the star’s trajectory, as shown in Fig. 15.1.

In this book we have been looking at various ways in which the relative positions and brightnesses of double stars can be measured in such a way as to contribute to the general knowledge of these objects. The main areas of opportunity can be summed up as follows

In this chapter I describe a typical observing session with the 8-in. (20-cm) Thorrowgood refractor at the Institute of Astronomy in Cambridge. The telescope belongs to the Royal Astronomical Society but is on permanent loan to the Cambridge University Astronomical Society and has been on its present site since 1930 (Fig. 24.1).

Cameras have developed significantly in the past decade; in particular, digital Single-Lens Reflex Cameras (DSLR) have appeared. As a consequence we can buy cameras of higher and higher pixel number, and mass production has resulted in the great reduction of prices. CMOS sensors used for imaging are increasingly sensitive, and the electronics in the cameras allows images to be taken with much less noise. The software background is developing in a similar way—intelligent programs are created for after-processing and other supplementary works. Nowadays we can find a digital camera in almost every household, most of these cameras are DSLR ones. These can be used very well for astronomical imaging, which is nicely demonstrated by the amount and quality of the spectacular astrophotos appearing in different publications. These examples also show how much post-processing software contributes to the rise in the standard of the pictures. To sum up, the DSLR camera serves as a cheap alternative for the CCD camera, with somewhat weaker technical characteristics. In the following, I will introduce how we can measure the main parameters (position angle and separation) of double stars, based on the methods, software and equipment I use. Others can easily apply these for their own circumstances.

The observations brought inside after a night at the telescope are little more than just raw data. A number of steps must be taken to convert the observations into meaningful data. These steps include expressing the time of each observation in a standard form and reducing the observed magnitudes of the individual components. The observations need to be reduced to some standard epoch so they can be compared directly with observations made at other times. This also requires corrections to be made for the effects of precession and proper motion on the position angle. Consideration should also be given to the effects atmospheric refraction might have on the relative positions of the components. A night’s observing can require almost as much time inside at the desk as outside at the telescope.

It is not necessary to possess expensive or advanced apparatus in order to begin making accurate measures of double stars. This chapter discusses three different techniques, in ascending order of sophistication: the ring method, the chronometric method, and finally the use of reticle eyepieces. Of these, the ring method is the simplest, requiring in its crudest form nothing more than an ordinary stopwatch with lap facility. By the addition of a crosswire and position angle dial, the observer can begin to measure closer pairs. Even an illuminated reticle eyepiece requires no great financial outlay, and permits observations comparable in accuracy with those achieved using a filar micrometer.

Eclipsing binaries are little studied by amateur astronomers: to order to observe them the keen observer needs to become a photometrist. This chapter sets out to describe the various types of eclipsing binaries, how to predict the times of minima and the means of measurement - telescope, CCD camera photometric filters and computers - and finally the way in which the reductions are made. The last part explains light curves obtained in several different observing projects, a critique of which is also given.

Today’s amateur astronomer has access to technology and reference information that one could barely imagine even just a decade ago. The march of technology has made electronics and computers both more sophisticated and cheaper, encouraging the savvy amateur to try an astronomical technique not usually thought of as being in the amateur arsenal, speckle interferometry.

In this chapter we move out from the Sun and look at some of the neighbouring double and multiple stars which have been observed for centuries. In some cases there are still secrets to be revealed. The beauty of a sunset on Earth has inspired poets and artists for millennia—what must it be like when there is not one sunset but two or more with each sun glowing in a different color. The chiaroscuro would be impressive to say the least. Not all double and multiple systems have different colors—some contain stars of essentially the same spectral class and therefore color (Table 9.1).

The structure of an image formed by a circular aperture was first formulated by Airy (1835). In a refractor, the effect of diffraction on the image of a star in the focal plane is to produce a series of faint concentric rings around a central star disk, the Airy disk.

The observation of binocular double stars is an absorbing pastime and provides a good introduction to some of the “showpieces” of the night sky. It may lead to more detailed telescopic study of these underrated celestial objects or be enjoyed as a hobby in its own right. Either way, it is a most fascinating branch of astronomy.

Like many branches of astronomy, the observation of double stars can be appreciated 5 at several levels. For those who enjoy the night sky, double stars offer some of 6 the most attractive sights around and they are particularly good in small telescopes 7 where the colours are much more obvious.

The details of your growing record of double star observations can easily be kept in a spreadsheet with columns included for position angle, separation, magnitude, and color. Those entries provide the raw data needed to describe your stellar journeys. However, the essence of what draws you to doubles may not be as obvious when you review your notes. What inspires you to observe double stars? Is it the challenge of resolving a close pair, or pulling a faint secondary out of its companion’s glare? Or is it the stunning beauty of a colorful duo or closely matched twins? Do you enjoy tracking the progress of short-period doubles? All of these passions and more can be readily captured by sketches in a way that vividly supplements your tabular data.

Even a cursory reading of the literature of visual double star astronomy is sufficient to show that the field has long been heavily dominated by the refractor, which remains the instrument of choice for many visual observers. It is not, indeed, hard to find statements backed by the highest authority alleging that for this type of observation a reflector must be of substantially larger aperture to match the performance of a refractor of given size. There is, however, no basis whatever in optical theory for such claims nor, as will shortly be seen, do actual results at the eyepiece sustain this perception of the reflecting telescope as second-class citizen. This chapter will demonstrate that, and how, a reflector of good optical quality, maintained in proper adjustment, can be fully the equal aperture-for-aperture of the best refractor, matching the latter’s resolution to the uttermost limits of visual double star astronomy, at least on fairly equal pairs. It is not amiss to recall at this point that the study of binary stars was founded by Herschel with reflecting telescopes and that its current limits have largely been set by recent observations with reflecting systems, both in terrestrial speckle interferometry and in the Hipparcos orbital observatory.

The PISCO project being carried out at I.N.A.F. ‐ Osservatorio Astronomico di Brera (Merate, Italy) since 2003 is described. The aims of the project are outlined and results of work carried out so far are given. Prospects of extending and improving the scientific reach of the project using more efficient detectors on bigger telescopes are discussed.

The astrophysical study of close visual binary stars presents many problems due to the degradation in spatial information by atmospheric turbulence. An image scanner, part of the instrumentation of the 1 m telescope at La Palma, is described which allows photometry of multiple stellar systems to be undertaken. The instrument is optimized for correct sampling of the atmospheric turbulence and uses a photomultiplier detector linked to a high-speed photon counting system.

Photographic astrometry of four radio stars has been carried out in a test program using the Wide Field Camera at the f/8 focus of the Jacobus Kapteyn Telescope (JKT). The accuracy of the positions is 0.04 arcsec. Comparisons are made with positions obtained by the Carlsberg and Bordeaux automatic meridian circles and with the radio positions measured with the Very Large Array

Using a short exposure, one dimensional area scanner, a programme of photometry on binary stars with separations

A new micrometer has been in operation on the Carlsberg Automatic Meridian Circle since May 1988. The zenith mean error for one observation has improved from O.″19 to 0.″14 and the limiting magnitude from 13m.2 to 14m.8. The first meridian observations of Pluto and observations of nine extragalactic objects are briefly discussed.

MERLIN positions of 12 radio stars are used to link the provisional Hipparcos reference frame to the International Celestial Reference Frame. The accuracy of the link using these radio stars is 2.3 milliarcseconds. Further observations are planned to check the accuracy of the link in the future.

We present astrometric, photometric and spectroscopic observations of supernova 1993J in M81, obtained with the Isaac Newton Group telescopes and the Carlsberg Automatic Meridian Circle. The spectral data set includes the first spectrum ever taken of SN1993J. The early spectra also yield an estimate of the total visual extinction, Av. This is combined with the photometric data to produce a bolometric light curve. Implications of the latter and of the spectral development are also discussed. The spectral evolution includes an infrared excess, which appeared after day 50 and may be indicative of an IR echo. The unchanging nature of blueshifted oxygen lines in the spectra argues for asymmetry in the distribution of the line-emitting region.

Spectral observations of Seyfert galaxies have been carried out at Fessenkov Astrophysical Institute of Kazakhstan (AFI) since 1970. The first spectrograms of about 48 objects have been measured and the radial velocities and absolute magnitudes of the galaxies have been derived. Some years ago, when the strong variability of spectra of Seyfert galaxies became known, we began a regular spectral monitoring program of 50 objects in this class (Table 1). The number of spectrograms obtained are given in brackets. In total, 2651 spectrograms were obtained in the red region of the spectrum and 1517 spectrograms in the blue.

A new micrometer has been in operation on the Carlsberg Automatic Meridian Circle since May 1988. The zenith mean error for one observation has improved from 0.″19 to 0.″14 and the limiting magnitude from 13m. 2 to 14m. 8. The first meridian observations of Pluto and observations of nine extragalactic objects are briefly discussed.

The positions of radio stars measured with respect to the VLBI network of extragalactic sources provides an important link between the optical and extragalactic reference frames. The establishment of this link was brought a stage nearer realization with the publication by Florkowski et al.(1985) of the radio positions of 20 stars measured with the Very Large Array (VLA) of the National Radio Astronomy Observatory, and the publication by Lestrade et al.(1985, 1988) of 10 stars measured with the VLBI network.

The contribution of the Carlsberg Meridian Catalogue La Palma Number 4 to the determination of the optical reference frame is discussed. This catalogue of almost 51000 stars provides one of the most accurate optical reference frames at the present epoch, having a density of 1 star per square degree, and an average accuracy of 0.″12 in position and 0.″003 per year in proper motion for stars with V 11 in the fields of benchmark extragalactic radio sources which can be used in linking the optical reference frame defined by the FK5 to the extragalactic frame.